The proposed study is an epidemiologic analysis of population data on adult cocaine use in the five U.S. areas sampled for the NIMH Epidemiologic Catchment Area (ECA) longitudinal field surveys. Baseline data on the 20,860 adults in the five ECA population samples were gathered by standardized interview methods between 1980 and 1984. A follow-up interview was conducted after one year. The primary specific aims for the proposed analyses are: To examine variation in prevalence of adult cocaine use within and between the five Epidemiologic Catchment Areas; and To seek out factors associated with being involved in cocaine use, some of which may prove to be risk factors for becoming involved in cocaine. We will test multivariate models of the nature and strength of potentially causal relationships between cocaine involvement and: (a) current or past history of marijuana use, other drug use, and early onset of drug use; (b) social maladaptive and Anti-Social Personality Disorder; (c) psychopathology, including mental disorders, syndromes, and symptoms; and (d) change in adult social roles, especially role gains that might be a moderating influence on cocaine use, and role losses that might increase levels of use. These aims relate to longer-term objectives of contributing to the body of research on the descriptive epidemiology of cocaine use in the U.S. and on causal modelling of adult cocaine use, its development and change over time.